1. Technical Field
Embodiments of the disclosure relate to semiconductor devices.
2. Related Art
Recently, low power dynamic random access memory (DRAM) devices have been increasingly in demand with the development of mobile products. In particular, the DRAM devices employed in the mobile products have been developed to reduce a current that flows during a refresh operation.
The DRAM devices among semiconductor memory devices may lose data stored in their memory cells as the time elapses even while their power supplies are applied thereto in contrast to static random access memory (SRAM) devices or flash memory devices.
To stably and continuously retain data in DRAM cells, DRAM devices are basically accompanied with operations for periodically rewriting the data in the DRAM cells. Such operations are often called “refresh” operations.